As one of future technologies required for an auto industry, there is an urgent requirement to develop vehicles suitable for responding to global warming, the exhaustion of petroleum resources, the deterioration of the urban air environment, etc., and to realize the use of energy alternatives to petroleum or to save energy, thus achieving high efficiency and reducing environmental pollution.
To satisfy this requirement, the development of a hybrid electric car which is capable of considerably increasing the fuel efficiency of a vehicle, in comparison with a conventional vehicle, has made good progress. The typical hybrid electric car has two power sources, namely an engine and an electric motor. Thus, according to the intended purpose, the hybrid electric car utilizes the engine and the electric motor at optimal efficiency, thus saving energy and reducing pollution.
One example of a hybrid car is a fuel cell vehicle which uses a fuel cell. Such a fuel cell vehicle utilizes a fuel cell system which uses pure hydrogen (generally, purity of 99% or higher) as fuel.
The fuel cell system applied to the fuel cell vehicle includes a plurality of hydrogen storage tanks which are charged with high-pressure hydrogen. A hydrogen supply pipe functions to carry hydrogen gas contained in the hydrogen storage tanks. A magnetic valve is installed between each of the hydrogen storage tanks and the hydrogen supply pipe, and controls the flow of gas through an opening and closing operation. A regulator reduces the pressure of hydrogen gas supplied from the hydrogen supply pipe at a predetermined pressure level. The hydrogen, whose pressure is reduced in the regulator, is supplied to a fuel cell. The fuel cell makes the hydrogen react with oxygen, thus generating electric power. A motor generates driving force using the electric power which is generated by the fuel cell.
The fuel cell vehicle having such a fuel cell system is schematically shown in FIG. 1. As shown in the drawing, a plurality of hydrogen storage tanks 2 is installed in the fuel cell vehicle 1. The hydrogen storage tanks 2 are mounted via bolts to a chassis cross member, which is provided on the lower end of a rear floor.
Specifically, the hydrogen storage tanks 2 include a front hydrogen storage tank 2A, a rear hydrogen storage tank 2C, and a middle hydrogen storage tank 2B. The front hydrogen storage tank 2A is located under a seat which is provided on the rear of the vehicle. The rear hydrogen storage tank 2C is located under a trunk. The middle hydrogen storage tank 2B is located between the front and rear hydrogen storage tanks 2A and 2C. Generally, the middle hydrogen storage tank 2B and the rear hydrogen storage tank 2C are disposed on opposite sides of the chassis cross member 3.
However, the conventional structure has the following problem. That is, in the event of a rear impact, the rear hydrogen storage tank 2C may be moved towards the front of the vehicle due to deformation. In this case, a pointed corner portion of the chassis cross member 3 can collide with the hydrogen storage tanks 2B and 2C, and thus break or damage the tanks, resulting in hydrogen leaking from the tanks, thus causing a serious problem.